js计算页面刷新的次数

<script language="javascript"> 
function window.onload() 
{ 
if(window.name==""){ 
window.name = "0"; 
} 
else{ 
window.name = eval(window.name) + 1; 
alert("已经刷新"+ window.name+'次'); 
} 
} 
</script>